I'd think the realistic gain will be variable if the pieces aren't being switched out for haste/mastery, since I assume you're using PE/EM which has a gain from haste via fire elemental and mastery is your personal damage obviously, depending on the fight duration it will swing from a gain like simcraft shows (thought it will be small) to a noticeable loss based on cooldowns. It is personal choice, and I'd say if it's showing such a small gain of 2000, the small utility the 4pc can give on some fights might actually be worth keeping it for, it's all preferrence.